Automatic friction lock



Patented Aug. 7, 1951 UNITED eagoallhf,

Weight oai-:any objectf-'supporteelby themcwabley I5m astwelli as'th'ef Weight? off the@ movable' member-itself? normally urgesy the movable mem;- berdwnWa-rdlya' The principle` off' theautomatic'W friction: look" Hereinafter 'dscribedi-is cafpabie: off broaziapp'lieH 20 cation and maybefused'iinmany-different struc#- tures ItE is f applicabie'- to 7anyfme'ehanis'm'fwhereL a'yariatin"o-f'tensicn or resi-stance Lto"'rn'overrreritA of a rod',l or-'similarfmemberg' Within arttibulail membere'isrequireds- The-friction-locliimaybe 25 usedf advantageously inadjustable-1 stands? for" supporting movingf picturescreens;` ligiits; ref-- 'ct'orsi dispiaywfixturesf and siinilardevices. Itj mayc also 1 be used* on tripods or any laboratoryf uses: for the'friction lock areonfextensibleeradio aerials; and" chairs stoolssor* other fi'xrnitureVA Wliicir'mayfbe adjustablein Height: 'Trie-above'p mentioned usesl are recited' to give a more-"corri"-A p'iete# understanding-entire -irwentionA and it will 35;

lief-understood thatT tire-*invention i`s= not limited;

to'these;specificuses.v v

Tli'estructureby 'which the variousre'sultsareL att'ainedl-wlrbe described'ifrconnection* with thea accompanyingdraWi-ng;inwliicli:

`li'g-ure 1- isiafragmentary-f ln'gitudinal sec-- tional' View throug-- a;2 tubular-housing and* an automatic friction lockVr holding a-slidablefrod 'inl adjusted'postion:witliin'thetubulariousing;

Fig; 2t isra'crosslsectionalview; takenialongftlie 4,5`

iorciiums. cl.- 28s-585 Figs'V 65%is la 'fragmentaryd'etail perspective-view? snowing the top' portionT4 off one` of-fftlie'A springs, ngersf'fofthelock;

Eig-f 7T is'- I a` cross l sectional view-y` taken 1 a-ong:

Figararis a=cross=seoticna1 View; similarlto Figa throughla modified'embodimentrof .thejns/ention: inf whi l h lthe rod-has afiround; crossisection ,g

Fig-Lw l0 isi ai detail i. perspective zviewtzsimilar; to; Fig. 4, of the disk adapted for use with tiiezrourrdi rod: of the; embodiment shown in;.Fig; 8; and

Eig-:.11.isiaisidnzelevationzof one-ofthe spring; fingers of.theilo'ckadapted,ioriuseNviththeroun'd: ro'dmf; the.' embodimenti-ofFigs 8i;

Inthe drawings; thelreferencernumeral.2E-indi@- catessaitubul'ar.housingawliich may ber-supported imuprrght; positionv by. any;- suitablef ba'see. (nota shown): The? housing; may bei* offA anyay desired: crosse.t sectional coniieruration; but: is shown, as; bengac-iroularf. An .inwardly extending rotubers ancezforms 'atled'gez'finsideithe housing forrsup'e-v portingrthefouteredge of aiunnelsshaped meme: bier ProtuberaneeK 3 i may.l be fcontinuousg. exfrtending entirely around thewcircumferenceiofgtiie: hou-singer ittmaycompriserarliscontimous .series ofi. projectionsi. spaced: aroundath'e: circumference; ofi tnerhousingatzthezsam'eilevei andrat' interi/alsa close.'V enough to.` furnish? adequate lsupporti for? membrerfrliii4 Anaaperture, insthe:bottom;v of member-:4i isi shaped to conformLtothefcross' sectionaliarea. ofaaslidable rodf Biand sis slightiylargeitopermit free"4 movement ofrtheitrodffthrough thei' apertures In the; embodiment'u of i the; invention :illustrated: in Figs. l; toi: '7, inclusive; rodxssis :ofjsquareL cross; section:A Theupperend ofrliousingZiseclosedaby means. of ai cap` 'I vsecuredt to ythe?lfiousing;byf;ai pluralityolboltsf.. Cap'l also hassanzapierturea Sith'rough'-whichrodzfextendsi In :cases- Wlfiereithel-rodi andi' housing comprisea azstandj theaobject to.besupportl'ad.:` is mounted oni the upperiendiof ro'dl'.

The frictional lock mechanism-ofithe-presenti; invention includes;-` a'f. plurality ofiA rela-tively; stiff springlngers; I Ilwhichiiare notched.adjacentatliei upper p'orticms` I I,' asf indicated at I2 and |3211? Fig-3` 6; to'iengageafdisk" Idipositionedin'housing@ Zffbetinfeenfv furmelsliaped" member' 4^r and@ cap2 1? Disk I4 is apertured, as indicated at I5 in'Eg;Y 4; toi-ntf arol-in'cifrodv 6; Ntches .1 I extendiugfom theedges-f of? aperture I stowardtlie perimeter ofiA the=dsklafre of iess Widtli tlianjltliesidsof'fapr# ture@ I5 -andtaredisposed vcentra-ilystb'ei'eof'so als? to leave projections I'I and I8 at adjacent corners of aperture I5. Notches I2 and I3 of each spring iinger I are interengaged with a pair of projections I'I and I8, respectively, to support fingers I0 on disk Id. Notohes I2 and I3 are slightly Wider than the thickness of disk Ill so as to permit fingers I0' to have a slight pivotal movement normal to rod 6.

The top end I I of each linger IIl is spaced very slightly from rod and extends inwardly into contact with the rod, from approximately the middle of upper portion II downwardly to the juncture I9 of this portion and the dependent bowed portion of the spring finger. This portion of each spring finger in contact with rod E constitutes a substantial area of frictional contact.

Each finger I is bowed outwardly between the juncture point I9 and its lower end Z. The lower end of each linger `engages funnel-shaped member 6i. A coiled spring 2 I, encircling rod 6, ispositioned between cap 'I and disk I4. Since cap 1 is fixed, the spring bears against disk I4 to urge it downwardly. The downward thrust of the spring is opposed by the relative stiffness oi fingers I0 and funnel-shaped member li, which is held against downward movement by protuberance 3. The upper portions of spring fingers I0 are normally held in fixed position with suicient frictional contact with the outer surfaces of rod 6 to hold the rod in any adjusted position within housing 2.

When force is applied to rod 6 to move it upwardly relative to housing 2 the initial application of force moves the lingers and disk I4 upwardly a very slight distance against the action of spring 2|. This movement frees lower ends 2@ ofthe spring fingers from contact with funnelshaped member 5 so that they can swing outwardly slightly, and upper portions II move into substantial parallelism with rod 6 to decrease the frictional contact between the spring fingers and the rod. As soon as the moving force against the rod is released, spring 2l reacts to restore the balance and the rod is held at the position to which it has been moved.

.Downward movement of the rod requires a greater force than upward movement `because downward pressure on the rod forces lower ends 20 of the springfingers against funnel-shaped member 4 and increases the bow of the spring iingers, thereby binding the upper portions of the fingers more tightly against the rod.

AIn assembling the mechanism, cap 'I is threaded on rod 6 and spring 2l is then positioned aroundthe rod. Fingers I0 are engaged with disk I4 by interengagernent of notches I2 and I3 with projections Il and I8 to form an assembly unit which is then threaded on rod 8. Funnelshaped member 4 is dropped into housing 2 so that it assumes the position shown in Fig. 1. The lower end of rod 6 is then threaded through aperture 5 in the funnel-shaped member. Cap 1 is then fitted around the outside of housing 2 and is secured in place.

The bottom oihousing 2 may be provided with a base to permit it to stand upright, and the top of rod 5 may be provided with any suitable fitting to enable it to support any specic article, such as a motion picture projection screen, for example. `Inthe embodiment of the invention illustrated in Figs. 8 to 11,.incl usive, a round rod 6 is substituted for square rod 6. It will be understood that the rod may beof anyother ,desired shape.

Fingers I0 have their upper portions II' rounded to fit the rod and are notched, as indicated at I2' and I3'. Disk I4 has a circular aperture I5', notched as indicated at I6', to provide projections Il and I8 adapted to engage notches I2 and I3. The drawing shows only two fingers I0 but it is obviousihat tlisnumb'er. may be increased.

Although two preferred embodiments 01" the invention have been described in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many details of structure may be modified or changed without departing from the ture described, except as limited by the appended claims.

I claim:

1. In combination with a rod, a friction lock comprising a plurality of spring lingers spaced circumferentially around said rod, said spring :lingers each having its upper portion positioned adjacent said rod and its lower portion bowed away therefrom, a disk embracing said rod and the upper portions of said spring lingers to hold said spring lingers against said rod, and a funnel- Sharped member engaging the lower ends of said spring nngers to increase the bow of said fingers when force is applied against said rod to move it in one direction and thereby cause` the upper portion of each spring linger to bind it more tightly against said rod.

2. In combination with a rod, a friction lock comprising a plurality of spring fingers bowed outwardly intermediate their ends, each of said said lingers whereby force tending to move said` rod downwardly will increase the amount of bow in said ngers to cause the upper portions thereof to bind more tightly against said rod.

3. In combination with a tubular housing and a rod slidable in said housing, a friction lock mechanism comprising a plurality Vof relatively stiff spring lingers, a disk in said housing supporting the upper ends of said spring fingers, and a funnel-shaped member mounted in said housing and engaging the lower ends of said spring ingers, said spring fingers each having a portion adjacent its top end engaging said rod to hold said rod in position within said housing.

4. A frictional lock mechanism comprising aY tubular housing, an apertured kcap closing the top of said housing, an apertured disk mounted in said housing, a rod fitting in said apertures and slidable longitudinally relative to said housing, a plurality of spring lingers fixed with relation to said disk with a portion of each ringer in contact with said rod, a funnel-shaped member engaging the lower portions of said iingers and held against downward 'moveinena and a spring urging said disk downwardly, thereby pressing the lower portions of said iingers against said funnel-shaped member and applying sui"- ficient force to the contact areas of said fingers against said rod tou hold said rod in any adjusted position within said housing.

5. In combination with a tubular housing and a rod slidable in said housing, a plurality of relatively stiffy spring lingers lpositioned in said housing, meansholding the lower portions of said fingers against downward movement, each of said fingers having its upper portion shaped to conform to the outer surface of said rod, a disk in said housing apertured to t around said rod, said disk being notched adjacent said aperture, said ngers each having its upper portion notched, the edges of said disk adjacent the notches in said disk engaging the notched portions of said fingers and thereby holding the upper portions of said iingers in frictional contact with said rod.

6. A frictional lock mechanism comprising a tubular housing, a rod slidable in said housing, a disk in said housing apertured to receive said rod, a plurality of pairs of projections on said disk adjacent said aperture, a plurality of spring fingers each provided with a pair of notches engaging said projections to support said ngers with a portion of each of said iingers engaging said rod in any adjusted position in said housing, and a member xed in said housing engaging the lower ends of said ngers to resist downward movement of said disk and ngers,

'7. A frictional lock mechanism comprising a tubular housing, a rod slidable in said housing, a plurality of spring fingers positioned in said housing and engaging said rod to hold it in any adjusted position in said housing, a disk in said housing supporting the upper ends of said fingers, a coiled spring bearing against the top of said disk urging said disk downwardly, and a fixed member engaging the lower ends of said fingers to resist movement of said disk downwardly.

8. In combination with a tubular housing and a rod yslidably mounted therein, a friction lock mechanism comprising a disk mounted in said housing and apertured to fit around said rod, a plurality of spring fingers supported by said disk in' fi'ictional contact with said rod, a coiled spring bearing against said disk to offer a slight resistance to movement of said rod in one direction, and a member engaging said fingers to provide greater resistance to movement of said rod inthe opposite direction.

9. A friction lock mechanism comprising a tubular housing, aelosure secured to the upper end of said housing, a funnel-shaped member fixed in said housing, a disk positioned in said housing between said closure and said funnelshaped member, a rod slidable in said housing, said closure, disk and funnel-shaped member each being apertured to fit around said rod, a spring coiled around said rod Ibetween said closure and said disk to resist upward movement of said disk. and a plurality of spring ngers depending from said disk, the upper portions of said fingers frictionally engaging said rod to hold it in any adjusted position in said housing, said funnel-shaped member engaging the lower ends of said fingers whereby downward pressure on said rod bows said ngers outwardly to increase the frictional contact of the upper portions of said ngers with said rod.

10. Ina friction' lock mechanism, a tubular housing, a rod slidable in said housing, a disk mounted in said housing and apertured to fit around said rod, a plurality of spring fingers each interengaged at its upper end with said disk, said interengagement permitting a slight pivotal movement of said ngers normal to said disk, the portion of each finger immediately below the point of said interengagement being held in frictional contact with the outer surface of said rod by said disk, a ledge extending inwardly of said housing Ibelow said disk, and a member supported on said ledge, said member engaging the lower ends of said fingers, said lingers being bowed outwardly between said frictional contact area and the lower ends of said fingers, whereby force tending to move said rod downwardly increases the bow of said fingers and causes a slight pivotal movement of said ngers adjacent said disk to increase the frictional contact with said rod.

BELA B. J UNKUNC.

No references cited. 

